There are numerous aspects of firearm usage and implementation. Certainly, there is a military application. Firearm applications, however, are broader than that. They are used in hunting, target shooting, etc.
To many people, firearm usage, maintenance, and care go far beyond a hobby. To many individuals, firearms are an avocation. To such people, safe use, precision, and accuracy of a weapon are paramount considerations. Consequently, bulk manufactured shell cartridges are unacceptable for use.
Each firearm has its own unique characteristics, and those characteristics vary over time because of wear. Even if there were no wear, however, as indicated above, every gun has its own individual characteristics. For example, throat, which is expanded radially with respect to the bore, does not have a length which is in accordance with an industry standard. That is, the throat length of each weapon will vary from that of other guns.
It will also be understood that clearance, as defined hereinafter, will vary even for the same weapon depending upon the characteristics of a bullet which is being used. The particular purpose for which the bullet is intended will cause the length and shape of the bullet to vary. Further, bullet lengths and shapes vary according to manufacturing and performance considerations. Consequently, the importance of precision in loading and reloading of a cartridge becomes even further highlighted.
In a typical weapon, the barrel has a rifled bore defined by a plurality of spiraling, alternating grooves and lands. At the rear end of the bore, there is a radially expanded throat in which the major longitudinal portion of a bullet, mounted at the front end of a cartridge case, is disposed when the case is received within the chamber. Since the diameter of the bullet closely approximates the diameter of the bore, there will be an annular space surrounding the bullet within the throat when the case is received within the chamber. The relative positioning of the bullet axially within the throat (measured in terms of "clearance"), the radial dimension of the annular space, and other factors will bear upon the safe operation, the accuracy of the weapon, etc. Over time and usage of the weapon, surfaces of the bore, including the grooves and lands spiraling therewithin, the throat, and the chamber (including the mouth to the chamber) will erode. Consequently, the characteristics of the particular firearm will change as time passes.
Typically, the chamber will determine the axial location of the cartridge case. The relative positioning of the bullet within the case will, therefore, vary the characteristics of the firearm. While, theoretically, all particular weapons having a particular caliber might be intended to have substantially identical characteristics, every firearm is unique. Consequently, the desire to load and reload bullets to cartridge cases results.
Clearance, as previously discussed, is the axial distance between the forwardmost location of the widest portion of the bullet and the rearmost limit of the bore, when the cartridge case is fully received within the chamber. For target rifles, zero clearance is sometimes best for maximum accuracy. That is, target rifles are, sometimes, most accurate when the bullet is mounted to the cartridge case at a relative position thereto so that, when the case is fully received within the chamber, the forwardmost location of the widest part of the bullet is closed up against the entrance to the bore.
On the other hand, such a relationship is not optimum for hunting rifles. With hunting rifles, some clearance must exist for reliable and safe operation. Zero clearance might be optimum for maximization of precision if other factors are not involved. As indicated above, however, for hunting rifles, some bullet clearance must be present.
Zero clearance has a number of drawbacks. For example, there is a risk that the case might be extracted and the bullet left wedged in the entrance to the bore. If that occurred, powder would spill out into the chamber, the mouth thereof, and the throat. The weapon would, effectively, be put out of commission. Again, the need for precise manual loading and reloading of cartridge cases becomes highlighted.
In current practice, an individual will effect loading or reloading by determining the maximum overall cartridge length, typically, arbitrarily. The bullet will then be seated within the mouth of the cartridge case and friction or press fit therewithin to accomplish this desired length.
As will be able to be seen, the way manual loading is accomplished in current practice is basically arbitrary. Consequently, uniformity and reliability are lost.
Further, new firearms should, shortly after purchase, be evaluated for freebore (that is, throat length) and allowance made by the manufacturer. It is important that such an evaluation be performed prior to using the firearm in order to assess how accurate the weapon will be in use. Such an assessment will be made with respect to any of a number of chosen projectiles.
Additionally, typically when cleaning firearms, the chamber, receiver, lands and grooves within the bore, and surrounding surfaces can become damaged by the cleaning rod and cleaning rod tips and brushes. Damage to these surfaces may result in loss of accuracy.
Further, the chamber, receiver, and surrounding surfaces can become contaminated by chemical agents. In the cleaning process, solvents and other chemicals are used, and deleterious effects can be brought to bear upon these surfaces.
It is to these problems and dictates of the prior art that the present invention is directed. It is a firearm tool which can be employed in manual loading to provide for a desired and uniform cartridge length. Further, it can serve to protect the various surfaces inside the weapon barrel during the cleaning function.